class picazzo3.wg.spirals.cell.FixedLengthSpiral(*args, **kwargs)

Spiral with incoupling sections that calculates its length. The total length is set by the property total_length and the inner size of the spiral will be adapted so that the total length of the spiral (including the incoupling sections) would be equal to total_length. The way this inner size is calculated can set using properties in the Layout view.


total_length: float and number > 0

Total design length of the spiral.

n_o_loops: int and number > 0

Number of loops in the spiral

trace_template: PCell and _TraceTemplate

Trace template used in the chain.


The unique name of the pcell

Other Parameters:

traces: List with type restriction, allowed types: <class ‘ipkiss3.pcell.cell.pcell.PCell’>, locked

n_o_traces: int and number > 0, locked

Total number of traces used in the spiral.



The inner size of the spiral is calculated by assuming a minimal inner_size and growing it in either the direction set by growth_direction. An error is raised when that is impossible to do with the set number of loops.



shapes: list

List of shapes used to build the traces


view_name: str and ( Alphanumeric string or Contains _$ )

The name of the view

incoupling_length: float and Real, number and number >= 0

length of the incoupling section.

spacing: float and Real, number and number >= 0

spacing between the individual loops.

flatten: ( bool, bool_, bool or int )

If true the instances are flattened

Other Parameters:

inner_size: locked

spiral_center: locked

auto_transform: locked


from technologies import silicon_photonics
from picazzo3.wg.spirals import FixedLengthSpiral
from ipkiss3 import all as i3

cell = FixedLengthSpiral(total_length=4000, n_o_loops=6, trace_template=i3.TECH.PCELLS.WG.DEFAULT)

layout = cell.Layout(incoupling_length=10.0,
                     stub_direction="H",  # either H or V
                     growth_direction="V"  # either H or V

# Checking if the trace length is indeed correct
print layout.trace_length()